The effects of Zn addition on the microstructure and mechanical properties of Mg.10Gd.3Y.0.6Zr(wt.%)alloys in the as-cast,solution-treated,and peak-aged conditions were investigated.Experimental results reveal that th...The effects of Zn addition on the microstructure and mechanical properties of Mg.10Gd.3Y.0.6Zr(wt.%)alloys in the as-cast,solution-treated,and peak-aged conditions were investigated.Experimental results reveal that the microstructure of the as-cast alloy without Zn consists ofα-Mg and Mg24(Gd,Y)5 phases,and the alloy with 0.5 wt.%Zn consists ofα-Mg,(Mg,Zn)3(Gd,Y)and Mg24(Gd,Y,Zn)5 phases.With the addition of Zn increasing to 1 wt.%,the Mg24(Gd,Y,Zn)5 phase disappears and some needle-like stacking faults distribute along the grain boundaries.Moreover,the 18R long-period stacking ordered(LPSO)phase is observed in the as-cast alloy with 2 wt.%Zn.After solution treatment,the Mg24(Gd,Y)5 and Mg24(Gd,Y,Zn)5 eutectic phases are completely dissolved,and the(Mg,Zn)3(Gd,Y)phase,needle-like stacking faults and 18R LPSO phase all transform into 14H LPSO phase.Both the suitable volume fraction of 14H LPSO phases and the fine ellipsoidal-shapedβ′phases make the peak-aged alloy with 0.5 wt.%Zn exhibit excellent comprehensive mechanical properties and the UTS,YS and elongation are 338 MPa,201 MPa and 6.8%,respectively.展开更多
The microstructure evolution and mechanical properties of Mg−15.3Gd−1Zn alloys with different Al contents(0,0.4,0.7 and 1.0 wt.%)were investigated.Microstructural analysis indicates that the addition of 0.4 wt.%Al fac...The microstructure evolution and mechanical properties of Mg−15.3Gd−1Zn alloys with different Al contents(0,0.4,0.7 and 1.0 wt.%)were investigated.Microstructural analysis indicates that the addition of 0.4 wt.%Al facilitates the formation of 18R-LPSO phase(Mg12Gd(Al,Zn))in the Mg−Gd−Zn alloy.The contents of Al11Gd3 and Al2Gd increase with the increase of Al content,while the content of(Mg,Zn)_(3)Gd decreases.After homogenization treatment,(Mg,Zn)_(3)Gd,18R-LPSO and some Al11Gd3 phases are transformed into the high-temperature stable 14H-LPSO phases.The particulate Al−Gd phases can stimulate the nucleation of dynamic recrystallization by the particle simulated nucleation(PSN)mechanism.The tensile strength of the as-rolled alloys is improved remarkably due to the grain refinement and the fiber-like reinforcement of LPSO phase.The precipitation of theβ′phase in the peak-aged alloys can significantly improve the strength.The peak-aged alloy containing 0.4 wt.%Al achieves excellent mechanical properties and the UTS,YS and elongation are 458 MPa,375 MPa and 6.2%,respectively.展开更多
The microstructure and mechanical properties of the as-cast and heat-treated Mg-4.6 Y-2.5 Zn-0.6 Zr-x Sn(x = 0, 0.2 and0.5 wt%) alloys were investigated in this work. The results showed that the eutectics have been re...The microstructure and mechanical properties of the as-cast and heat-treated Mg-4.6 Y-2.5 Zn-0.6 Zr-x Sn(x = 0, 0.2 and0.5 wt%) alloys were investigated in this work. The results showed that the eutectics have been refined with 0.2% Sn addition and it has no effect on the phase category of the alloys. However, Sn3 Y5 phase was found in 0.5% Sn-added alloy.After heat treatment at 520 °C, the transformation of the long-period stacking ordered(LPSO) phase takes place in the Mg-Y-Zn-Zr alloy, but the transition is not completed in the alloys containing Sn. In addition, during the heat treatment, the mechanical properties of Sn-free alloys are significantly improved, and the strength of alloys containing Sn does not change much. Through observation and analysis of the microstructure and mechanical properties, it is found that Sn addition hinders the process of a0-Mg ? a-Mg ? 14 H and the process is the key to the transition of 18 H-LPSO to 14 H-LPSO.展开更多
基金Projects(51774254,51774253,51701187,U1610123,51674226,51574207,51574206)supported by the National Natural Science Foundation of ChinaProject(MC2016-06)supported by the Science and Technology Major Project of Shanxi Province,ChinaProject(201601D021062)supported by Shanxi Province Science Foundation for Youths,China
文摘The effects of Zn addition on the microstructure and mechanical properties of Mg.10Gd.3Y.0.6Zr(wt.%)alloys in the as-cast,solution-treated,and peak-aged conditions were investigated.Experimental results reveal that the microstructure of the as-cast alloy without Zn consists ofα-Mg and Mg24(Gd,Y)5 phases,and the alloy with 0.5 wt.%Zn consists ofα-Mg,(Mg,Zn)3(Gd,Y)and Mg24(Gd,Y,Zn)5 phases.With the addition of Zn increasing to 1 wt.%,the Mg24(Gd,Y,Zn)5 phase disappears and some needle-like stacking faults distribute along the grain boundaries.Moreover,the 18R long-period stacking ordered(LPSO)phase is observed in the as-cast alloy with 2 wt.%Zn.After solution treatment,the Mg24(Gd,Y)5 and Mg24(Gd,Y,Zn)5 eutectic phases are completely dissolved,and the(Mg,Zn)3(Gd,Y)phase,needle-like stacking faults and 18R LPSO phase all transform into 14H LPSO phase.Both the suitable volume fraction of 14H LPSO phases and the fine ellipsoidal-shapedβ′phases make the peak-aged alloy with 0.5 wt.%Zn exhibit excellent comprehensive mechanical properties and the UTS,YS and elongation are 338 MPa,201 MPa and 6.8%,respectively.
基金the financial supports from the Natural Science Foundation of Hunan Province, China (No. 2018JJ2365)the Outstanding Youth Scientific Research Project of Hunan Education Department, China (No. 20B533)+3 种基金the Key Scientific Research Project of Hunan Provincial Department of Education, China (No. 20A455)the Science and Technology Innovation Program of Hunan Province, China (No. 2020RC1011)the Graduate Scientific Research Innovation Project of Hunan Province, China (No. CX20211280)the Science and Technology Innovation Leading Plan of High Tech Industry in Hunan Province, China (No. 2020GK2033)。
文摘The microstructure evolution and mechanical properties of Mg−15.3Gd−1Zn alloys with different Al contents(0,0.4,0.7 and 1.0 wt.%)were investigated.Microstructural analysis indicates that the addition of 0.4 wt.%Al facilitates the formation of 18R-LPSO phase(Mg12Gd(Al,Zn))in the Mg−Gd−Zn alloy.The contents of Al11Gd3 and Al2Gd increase with the increase of Al content,while the content of(Mg,Zn)_(3)Gd decreases.After homogenization treatment,(Mg,Zn)_(3)Gd,18R-LPSO and some Al11Gd3 phases are transformed into the high-temperature stable 14H-LPSO phases.The particulate Al−Gd phases can stimulate the nucleation of dynamic recrystallization by the particle simulated nucleation(PSN)mechanism.The tensile strength of the as-rolled alloys is improved remarkably due to the grain refinement and the fiber-like reinforcement of LPSO phase.The precipitation of theβ′phase in the peak-aged alloys can significantly improve the strength.The peak-aged alloy containing 0.4 wt.%Al achieves excellent mechanical properties and the UTS,YS and elongation are 458 MPa,375 MPa and 6.2%,respectively.
基金supported financially by the National Natural Science Foundation of China (Nos. 51774254, 51774253, 51701187, U1610123, 51674226, 51574207, and 51574206)the Science and Technology Major Project of Shanxi Province (No. MC2016-06)the Shanxi Province Science Foundation for Youths (No. 201601D021062)
文摘The microstructure and mechanical properties of the as-cast and heat-treated Mg-4.6 Y-2.5 Zn-0.6 Zr-x Sn(x = 0, 0.2 and0.5 wt%) alloys were investigated in this work. The results showed that the eutectics have been refined with 0.2% Sn addition and it has no effect on the phase category of the alloys. However, Sn3 Y5 phase was found in 0.5% Sn-added alloy.After heat treatment at 520 °C, the transformation of the long-period stacking ordered(LPSO) phase takes place in the Mg-Y-Zn-Zr alloy, but the transition is not completed in the alloys containing Sn. In addition, during the heat treatment, the mechanical properties of Sn-free alloys are significantly improved, and the strength of alloys containing Sn does not change much. Through observation and analysis of the microstructure and mechanical properties, it is found that Sn addition hinders the process of a0-Mg ? a-Mg ? 14 H and the process is the key to the transition of 18 H-LPSO to 14 H-LPSO.